Protective switch



Sept. 12, 1950 w, H 2,522,048

PROTECTIVE SWITCH Filed May 5, 1945 4 Sheets-Sheet 1' II m 8 #71 r I A $7 561% START :25; g!

i O /5 a /6 0 1 60 a! 5 80 a! 5 a0 ,0

Sept. 12, c w KUHN PROTECTIVE SWITCH 4 Shqets-Shfeei 3 Filed May 5, 1945 Sept. 12, 1950 c. w. KUHN 3 8 PROTECTIVE swrrca Filed May 5, 1945 4.Shets-;-Sheet 4 Patented Sept. 1 1950 ClarenoeW. Kuhn; Wauwatosa, Wis.', assignor to Cutler-Hammer; me, Milwaukee, Wis., a'conporationioft- Delaware Application ay 521945, SerialNo. 592.209 I This inventionrelates toimprovementsin protective switches, and whilenotlimited th'ereto is particularly applicable to-overload switches ofthe' thermally responsive type" employed for controlling" a translating circuit through the medium of an electromagnetic contactor';

An object 'of-"theinvention is to provide -protective switch ofa-type comprisinguriits which may be assembled intovarious-compositeforms tomeet different needs, especially as regards responsiveness to a differentnumber-bfphases of' 23 Claims. (Cl. 200-116) an alternating current circuit-when such is" the controlled circuit;

Another-object is-to embody in separate units I a switch mechanisnrandathermally responsive control means for such switch'unit; andto pro-- videfor useof the switchunit' in conjunction with oneor amultiplicity ofthetherma-lly responsive ccntrol'units}-acccrding tOIlShC number of lines of the controlled' circuit? to which the switch is to bemade-sensitive.

Another object is-to provide a switch unit of the type-aforementioned; containing" a switch of the free trippi'ng type. v

Another object is to provide" inconjunction with suchv a switch un-it' and' thermally respon sive, tripvunits: therefor, a" momentary" con-tact switch. unit-,-v to afford e; composite device l'iavin-g separatestart andstori switchesoperable at will, the; manual .operatingtinember forthestop switch constituting also as reset-' elernent for thest'hermallet responsive trin units same.

object isawtoiso-zform all aforementioned unitsias :to; afiordavery com-pact: composite-device or: any one s of' the of small. dimensions: forlth'er servicerequired thereon? anctherrobject i'sato so construct" the switch unitpiwhichiis. subject to: the:- control- 0fthe thermally responsive unit or unitsas to indicatewhethcrasuch-switch is set- -irr cl'osed position or is in trippedapositi'on:

Anothers object 2 is to "utilize in thethermally responsive? solder type thermal elements witlrgh'eat: coils atherefor and to provide ionany ones-ofanumber of predetermined relativead lustments: oi each solder element and its" heater coil iimasvery simpl'e and: convenient manner.

Vaniousxother objects and: advantages of the invention willlhereinaiter appear: 1

The accompanying d1awingiliustrates one embodiment" of the inventicn which will now be describectit being-understood that theunits illustraitediarersusceptibleiof modification without de partingafroml the: scope "of the appended claims and that the composite device selected for tration is only one of numerous devices which maybe produced using'units of the forms shown.

In the accompanying drawing,

Figure 1- is a'frontelevat'ional view of acomposite device which has separate start. and stop. switchesand" in which the stop switch has a' ing current circuit; I n v Fig. 2*is aside elevational view of Fig. 1;

tripping unit for each line of a 3' phase alternat- Fig. 3 is a bottom plan view of the device or" Figs-1 and 2; I

l ig. 4 1s an'endelevation or the device ofFigs:

l to 3;

Fig. 5 isan enlarged side Fig. '6: is an enlarged elevational view partly;

in section of "the: stop switchunit' of Fig. 1

Figs. '7 and 8 are more orless schematic views depicting the different relative movements to which the contacts of are subject;

Fig. 9-ShO WS"lni disassembled relation parts of the contact actuatingfn echanis'm of the-switch of Fig. 6;

Figs. 10- and "11 show'the partsof Fig. 9- assem bled and occupying different relative positions;

Figs. 12 and 13 are enlarged detail views show ing in different relations parts causing the elements ofFi'gs. IOandll to assume the different relations shown therein;

Fig. 1-4== is anenl'arged detail view of a terminal plate employed; and

Fig. 15 isadiagrammatic showing of of the deviceshown in Figs. 1 to 133 Referring to Figs: 1 and 2, the composite device comprises a unit I containing the start switch; a, unit 2 comprising the stop switch and three like units 3' containingthermally responsive trip means for-the stop switch of unit 2. Externally th'e'switch units a reidentica-I, each being arrangedbetween the'center unit 3 and one of the extreme units 3-130 produce a compact and symmetrical-com-poeite=device, the several units being firmly secured together by through rivets 4 and 1 5. The-throughrivetstand 5- also secure the uni-ts within end*rjrla-tes't and l which as shown inF'ig. 2* are of right angle form, the portions 8 of each being extended to provide oppositely disposed supporting lugs-or ears 9and ill.

Each of the units comprises a recessed; in-. su'lating housing open" at' the bottom and pro? vid'ed adjacent w the-bottom with side open-' ings' 'for apurpose" hereinafter set forth. The" illuselevation partly in section-of oneof'the thermally responsive trip-1 the switch shownin Fig. 6;

one use abutting faces of all units are fiat and for economy of space the switch units have relatively thin sections for insertion between the thermally responsive units 3 and enlarged portions to receive push buttons I i and I2, respectively, and also to accommodate parts hereinafter set forth. The housings of the thermally responsive units 3,

as will be apparent from Figs. 2, 4 and 5, have terminal supporting faces l3 and I4- at different levels, whereas each switch unit has terminal supporting faces l5 and It at a third level, there-' by adequately spacing the terminals and rendering all readily accessible. The aforementioned side openings in the switch units and thermally responsive units are substantially as shown in the lower portions of Figs. 5 and 6, extending upwardly suniciently to give clearance throughout the length of the composite unit for a rocking trip bar 29, Figs. 3, 5 and 6, which has endbearings 2|, Figs. 3 and 4, in the end plates 6 and 1. This trip bar which will later be described in detail, is common to all of the thermally responsive units, to be actuated by any or all of the same, and it acts upon the stop switch to trip the same, the start switch being entirely independent of the trip bar. For closure of the under side of the several units there is preferably provided a sheet of insulating material 22, Figs. 2, 5 and. 6,

which is supported at its ends between the bottom edges of the end units and the right angle portions 8 of the end plates 3 and I.

The start switch of unit I is merely a normally open switch to be closed by push button ll so long as said push button is held depressed, and as it may be of any one of a number of well known forms its construction is not illustrated in detail. Such switch is schematically shown in the diagram of Fig. 15 as comprising a pair of stationary contacts and a bridging contact operable by push button I I. As will be understood, the switch is biased to open position, and as shown on Fig. 1 the switch has terminals 24 and 25 which are integral extensions of its stationary contacts, which contacts may be of the form shown in Fig. 6 for the stop switch.- In the case of both the start switch and the stop switch the combined contacts and terminals are secured to the switch unit housings by screws 26 threading into sockets 21, Fig. 6.

Referring to Figs. 6 and 9, which show the switch to be controlled by the thermally responsive elements, said switch comprises stationary contacts 30 and 3| and a movable bridging contact 32. The bridging contact 32 is an in-- tegral part of a member 33 connected to the stem part 34 of push button 12, said push button being biased by spring 35 normally to effect engagement of bridging contact 32 with contacts 30 and 3|. As shown in Fig. 9 the stem part of the push button is relatively short and has an opening 36 adjacent its lower extremity to receive a pin 31 by which the contact carrying element 33 is attached to said stem part. The element 33 extends downwardly beyond the stem part of the push button and at its lower extremity has a projection 38 better shown in Figs. 10 and 11, to cooperate with a stepped cam member 39- carried by the trip bar 20, of the several thermally responsive units. Also the push button stem part 34 has attached thereto through the medium of the pin 3'! an element 43 to coact with a laterally extending lug 4| on the trip bar 20 (Figs. 3 and 6). The upper portion of the element 40 aligns with the stem part of the push button and at its upper extremity has a projecting lug 42 which '33 extending downwardly from the pin 31. The

openings for the pin 31 provided in the elements 33 and 40 are larger than the opening provided in .the stem part of the push button, the pin 31 being providedat one end with a head 41 and having its shank-adjacent the head of a diameter to snugly fit the opening in member 40 while having the remainder of its shank of reduced diameter-to pass through the smaller opening 36 in The pin is passed the push button stem part. progressively through the elements 40, 34, 33 and a tubular element to be loosely fitted into the opening in the contact carrying element33. The

tubular element 48 carries a helical spring 49 to be. confined between the faceof contact carrying r element 33 and a collar 50 riveted onto or othera wise secured to the pin 3'! for securement in assembled relation of the elements threaded by.- the pin. It will thus be seen thatwhile all of- 1 the elements 33, 34 and 40 are mounted in alignment the contact carrying element 33 is per-- mitted a rocking motion, (Fig. lllagainst the;

pressure of spring 49, with the lower extremity of the stem part 34 of the push button as its fulcrum and the downwardly extending part of element 33 having clearance for suchrocking motion'by virtue of the curvature of the extremity of the i overlying element. 4ll.- Such rocking motion is imparted to the element 33 by coaction ofthe. projection 33 thereon with thecam member 39:1

As indicated in Figs. Hand 13, the cam member 39 has surfaces 5| and 52'atdiiferent levels and a connecting inclined surface 53. With the pro-,

jection 3B of member 33 in engagement with the surface 52 the element33 assumes the relation to the element 34 depicted in Fig. 10, whereas as the projection rides over the camming surface 53 onto the surface 5|, element 33 is tilted as de-' picted in Fig. 11, the cam part 39 being so mounted on the trip bar 20 that the projection 38 normally rests on the surface 52 and rides ontothe surface 5| only when said trip bar functions under abnormal conditions. a Fig. 6 shows the aforedescribed switch parts in their normal relation with thecam part 39 disposed to permit the part33 to'assurne the position shown in Fig. 10. Under such conditions the bridging contact 32 engages the under sides of the contacts 30 and 3| and is firmly held thereagainst by the bias exerted on the push' button by the spring 35. It is thus possible at any time to disengage the bridging contact 32 from its stationary contacts by merely depressing the push button l2 against the action of spring 35, which spring of course returns the bridging contact into engagement with the stationary contacts' upon release of the button. This .move-" mentof the bridging contact by depression of the push button is depicted in Fig. 7, whereas Fig 8 depicts motion of the bridging contact as a function of automatic tripping resulting from rocking of the trip bar 20 and the cam part 39. Such rocking of the trip bar effects the aforedescribed rocking motion of the contact carrying element 33, as depicted in Fig. 11, and this re-- tt htrmqtlhgtthe t r dgmw mect ls aterhllt outjnfienga m nt. with, it steti ne-wt ntati e qtqezgtq edwby dpttestlinesih ig-=1 T e eu gn. hehiased husht tto t istelievedt l te t aaint.

by the wi h ontastsfllt ahsll i and s id utht 5 k .W ih centeszt is -'-Q shbulclthe pushbutton be manually restrained, gain t upw r IhQti h f Or he. mpe tjfifi t t 20,, he}. eme t ficieht t efiq d itfi lgagels e ch t ct th anataawteganam asiwill later appear the trip bar zflfl isspl i gg ac;- fid mimp a o h la era m i n' ofrthe me r. .8 m ui k d enghg meht 9 5,25; the Contacts even though the pushbutton t2 be manually restrained against meyement by spring 35; The switch just described; is after tripping therein; resettable by-me1 e1y depressing the push butte'm I21 Such; operation of the push'button lz-meves -the-bridgihg contactto the plane below theste tipnary contacts; as clepieted indottedlines iwI ig 7 Mereover-in sq moving the briclging eentact dew-nwar'dly the push button meves the eurted extremity: 450i element 48- downward- 1yagainst the lug M on the rocking trip bar to' ro'ckisaitl tripbar and cam member 39 m 2, direction texpermitelement 33 to move from the tilted positfilenushewn in Fig; 11 to the pesition shown -4 lflmhereb-y upon release of the-push button-the bridging-contact:'fiz wifl-sbe permitted agemntoaengege thehundensidesmithelcontacts"" 3i3--ang1:3:lr: Asu wi wbe undensteod; thewparts are" so-c0nrdinated as to; permit the member 3km 4, rO-Qks :bzwk to marmal" position only: after depresn emofeth vbn dgin contact intoaa plane; S'llfn fiQiQQfqlXr below; the com/ante J3; 85116213.! as to me 1 sure against re-engagement of said contacts; by latetat 1m went- 0f.- th bti ihgtcantact. It 50 t e t me h hm -the 9tn$ metdeSQlZi Bd .na J- st N t v of FWWySiMPE we. v. tru eh being the eaten/ t the hpl singtilhistnatedv The hqwtng 3 ret-e t mihtsdph ieo h ileum-q; except for the upper portion which is en1arged te qn fiqfi lififl tz push button; and; 9. eceive-an t at ehh ec a d: e minals, he nlhrge ltpush t Qn-I ce v n pct ioh o thezh h ng; th rewithm n m er oitsmt s fitfiplfidaes 5H9.- o m down m sier he uth-butmheht meet fqtme it klfifipliing 3,5 which is. attihl y" ceme ts:d1 Within the push button l2. Tlgeee leqges 19m; e tale supp/Q2 o w tthm the 1 .1.1. h h in i h. ty exc pt t r the s a mlwh nt cts fid-b ihfipllfil .bufiQQfififiIll pent A he 1 tiqnery QQI W-MS (i1 W12 i:HLIQMSIAJ QQDGWHQQ, rewith of t e d in contactizwretst ainthe pus utton. hthe. .desixedmrmel ntermed at pols hem thus 1. .0 the q nhett ontbhtw e e. musing: an th swi qh-m thenism is 1 1 9 14 53 able-m p isin QLdeL-mstraih gutt d a attqherwebh eq stiflyem: .1; 31%

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eem 1 g em areseeted amt: astsh w tt n. 6. F et? t f EII QQ; nterm nt 1 0- tpht no he 1 l t sqtn -guid che ism .41.12

h otkhe QhtI m twheel 11mm.

cuit'by including fin'such circuit its heat 011,

and each unit will afford independent operating means for thetrip bar common thereto and acting upon the switch of unit 2. Also it will be understood from the foregoing description that continued restraint of the element 60 of any unit will in nowise interfere with operation of the 'trip'bar by any other unit and th'at any released'eleme'ntfifl may be reset and latched by reverse movement of the trip bar through the medium of the stop and reset push button l2 and the element 45 operable thereby and engageable with the lug Al on the trip bar.

In practice it is desirable to provide for adjustment of each heat coil longitudinally of the stem surrounded by itvthereby to adjust the respective thermalidevice for trip at a selectable value of the current traversingsaid coil. Also it is desirabl e to discourage tampering with the adjustment byinexperienced persons and to have a safejlimit'oiadjustrnent. To these' ends provision is made,in each unit for several predetermined adjustments which are easy to make and unlikely to'be disturbed by inexperienced persons. More specifically each coil is provided with oneofiset' terminal shown in Fig. 4 as the I upperterrninal but injFig. 5 as the lower terminal, and it will beobvious that one given adjustment is afforded byimer'e reversal of the coil on its support; the degree oi adjustment being determined by'the degree of offset oijthe one terminal mentioned. A lso each. coil has for both of its terminals'steppcd terminal plates 80 best shown in Fig' 14:, which plates' 'are fixed to the supporting block and are "provided'with binding screws 8! and 82 on difierent stepsof the plates, the bindmg screws aifording a medium for attachment of the plates to the block. Thus iurtheradjustment of the heat, coil maybe effected by securing its terminals against different steps of the plate 89 and obviously witha coil provided with an 0&-

set terminal and with two-step terminal plates enable the coilto be assembled in four different v predetermined relations with thestem of the thermal device sensitive tothe heat of said coil..

Such adjustments will ordinarily be sufiicient.

As showni'n Fig. 15, the composite device selected for illustration may be employed to controlen electroresponsive main switch for a 3- phase alternating current translating circuit. The. inswitch' designated as 83 is shown as having .itscoilconnected across the outside supply lines through a resistance r and the contacts 3 .3. .and12,bithes t 2 Qfu t e c taots'of theiswitchof unit are designated asv B4, 85 and 86 and; these contacts control a short circuit forthe resistor 1'. Thus assumin the contacts 39, 3l and 32 to'be set in an engaged relation n'lomentary engagement of contacts 84, 85'and .86 establishes an energizing circuit for the main switch, whereas disengagement or the.

latter contacts re-inserts in the resistor T which is of a valuesuch that the current flow permitted thereby will maintain he Switch 83 energized ut will be insufficient to effect closure, of said switchwhen in open position. The heat coils of the units}; are respectively included in] the'three branches of the translating circuit, and as hereinbeiore indicated abnormal increase in current in any one of said coils as a result of abnormal conditionsin the corresponding branch of the translating circuit provides for tripping the contact' 32 to interrupt the maintaining circuit of the switch 33, thereby ,efiectinginterruption of the translating circuit. Thereafter'the antiserum as '32 may be la dscape; f;

pression of the push button l2, as earlier described, but without again energizing the switch 83 until the push button I l is depressed to again 'momentarily short-circuit resistor r. L a

-As will beunderstood, the number of units 3' employed maybe varied according to th pro.-

tectiondesired, and the start switch may if desired be omitted from the composite device. Also v it will be understood that whereas in the com-H; posite device shown each pair of units 3 has a switch unit interposed between the same, such units might be grouped together with a switchand threeiotheriof said units being alike and eachtcomprisinga tripping instrumentalityior a certain one of said switches, said units being:

arranged with, each ,switchunit, between two of said three like units and said three like units and the switch controlled thereby having'interconnections which are concealed by the composite enclosure of the composite device and which 9.1- ford said tripping .instrumentalities joint and in- I dividual control of the lastmentioned switch.

2. A composite'device comprising individually enclosed units secured together in an intimate relation with' unitary appearance, certain of said unitscomprising only circuit making and breakingmeans and other of said units comprising onlyelectricallycontrolled trip means for certain of said units-all of said units having wiring' terminals exposed on one side of the com-' posite device, andthe composite enclosure providing seats for said terminals at three'difier ent levels, one for the terminals 01 said circuit making and breaking means, and two for the opposite terminals of said electrically controlled trip means;

3. A composite device comprising an individually enclosed switchunitand an individually enclosed tripping unit for said switch unit, said units being secured together inan intimate relation with unitary appearance and having 'in-" terconnectio'ns' concealed by their enclosures collectively, saidtripp'ing unit being prune thermally responsive type and having a heat coil and stepped terminal plates therefor to'aflord i predetermined bodily adjustment of said coil ax- 4. A thermally responsive trip unit having a sensitive element and a heat coil for said element, said unit carryin stepped terminal plates for electrical connection and support of said coil, said coil being, shiftable from one step to an- I other on said plates for adjustment relative to said sensitiveelement.

5. A thermally responsive trip having a ment, said unit carryin stepped terminal plates for electrical connection and support of said coil, said coil being .shiftable from one step to ansensitive element and a heat coil for said eleother onsa idplates for adjustment relative to i ,said sensitive elementiand said coil having one Q of its extremities oifset 'to afford by reversal of "bar interconnjec m 'sa a switcli u'ni t an'di vsal'zi mp units fand doncealed the composite enj'closure v of the "composite rdevice, said rocking trip barbe'i'ng separatelyfsupported by' sa'id composite i Osureo ua'l'ly enclosed sit/itchunit,v individually enclosed units comprising "tfi ping instrumentalities ior 'saidswitch it 'fbeing'securedtogether an ifn f fth'ianrii'tary appearane as with the s 'unit interposed be- S "d a frocking'tilp tween'twdoithejtr v "barinterconnecti" aid switchunit andlsaid ti'ip 75A composite'deyice cdiiiiqrii'singanmdividunits'farid'conceale' bythe coniposite enclosure e composite device, said f trip bar and said switch tripping-"operation of said bar by said instrjum'entalities v collectively or individually and .fffo resetting of said 'instrn nental'i'ties 'byreverse when free of sai'djlatching means to effect tripping movement of said bar, said element and said t'rip bafinterfitting with play therebetween permitting reset of said eiem nt in its latched position by reverse movement of said trip bar; and allowing trippingmoveme'nt of said bar by other means while saidelement remains latched.

v 9. The combination with vaswitch unit having a rocking trip bar,'of a 'tri'ppi'ng unit comprising an element'forme'd to 'be slipped'into interfitting relation with said bar to constitute an operating ,lever therefor, and said tripping unit further comprising electrically controlled latching means forsaidelement, and'a spring exerting pressure on said element to hold itin cooperative relation with said trip bar and to cause said element when free .of,sai'd latching';means to efiect tripping movement of said bar, said element and said trip bar having interengaging parts includinga ii-shaped projection on-one engaging ina wider \Y-shaped notch in the other and affording a positive operative connection but allowing tripping movement of said bar byother means while said element remains latched.

10. An enclosed switch unit comprising stationary contacts, a bridging contact and snpporting and operating means for sald -bridging-contact including a push button anclbiasing means, said biasing means yieldinglv holding said bridg ing contact in 'engagementwith vsaid stationary contacts subject to diseng'agementby. said push button through movement oflsaid bridging contact perpendicularly of the plane of said stationary "contacts, said supporting and operating means further including means affording sliding disengagement of said bridging contact from said stationary contacts" followed 'by' aright angle [ping instr'umentalitie's" being connected "for s'witch unit haying etching means for movement of said bridging contact underthe -"i-luence .of,.sa'idi biasing, means to--main'tain :sai'd pontact'sdise aged pending ag'iven subsequent operation oflsal usjhbutton. 7141. 'An len'clcsed Lsf 'h unit comprising statfionaryicontactsy a bi d'ging contact and supand 'operatingineans vfor said bridging Con act in" iidi ng "a vpusl i-jjbutton and biasing biasing means yieldingly holding L p tact engagement with said 'st'ationafy contacts subject to disengagement by said push button through movement of said bridging contact penpendicularly'=o f the plan-e of said stationary contacts, said supporting and operating ineans lidnther including-means affording sl disengagement of said bridging Goni "said stationaz y contacts followed 'bya mfoyemen't oi said bridging contact v r if 1e nfluence of said biasing nqeans to "20 Ernain ea 51 contacts disengaged pending a given bseqpent operation of said ipusl but ton, ,saidllpush Zbuttonloccu pying-an intermediate position when-said -eontacts engage and assumingan, e gt ienie positionwhen said bridging contact 's moved by said I biasing means following s'l'l lngldisengagement of saidbridging contact tIIeTstatioi arycontacts. I 12; An venclosedflswitchuni-t -comprising-staf't'ionary .contacts a bnidg-ing contact, push buttori sec-iproeably mounted in' said unit and pro- ,jecting therein om, rneans "biasing -said-push button-outwardly; and-irrieansconnectedto-;-andsup ported bysaidpush gbutten totsupport-said bnidgi-ng contact normally engagement with 1 said a Lona contacts su bxieettto disengagement-by ,dfipllQS SlO oi saicl pu's h button, the last specified Jr eans- "affording. also sliding disengagement 0f v bridging contact from said stationary contacts for -following--- evement .p erpendicularly of vtiie plan of said stationany contacts as a r 1 v ie inem ans I t co pos giev-ice acompnising a -:switch ctri ally contrelled'tripunitand iritere n s -.tl'rerebetween, sa id iswitch unit com a p ist up ton ing means=|biasing the same in-fiGHEB QQIGQtIiQH fiBd' means connected to said "push vbutton to supportkSa/id bridging -contaet 1 y i-H eBQaQEmGnt with said stationary 4 se l/119113013 130 disengagement by depression V puSh;;-blltm, ;t1 le itast specified imeans afiordinggalso sliding "disengagement of said onta ctef neen \sai'dwstationary contacts jar; rfoliewng movementi as said {bridging contact perpendicularly of the plane of said stationary contacts its-1a tnnetiomof-.thenbias yet said push b tte -men d (213D mp n m ans acting -thmn said interconnections with said switchi- 120", i-fiect the aforementioned sliding disengagement ofesaid bridging:icontact irom said 'S Et'iQBQEX'F QnWEQi :1 4. "A compcsiteiedeyice comprising :a switch unit, @WflfiQtficalli i controlled trip unit atedinterconnections atherebetween, said switch co ingsta 'onary contacts, a bridging con-- I a push button1 having+means biasing the ten ta canary nontacts, a-bnidging-contant tionary contacts as a fin'iction of the bias of said push button, and said'trip unitcomprising means acting through said interconnectionswith' said switch unit to effect the aforementioned sliding disengagement of' said bridging contact from said contacts.

- 15. -A composite devicecomprising a switch unit, an electricallycontrolled trip unit and interconnections therebetween, said switch unit comprising stationary contacts, a bridging contact, a push button having means biasing the same inone direction,' -'and meansconnected to said push button to support-said'bridging contact normally 'in*eng'agementwith'said stationary contacts-subject to disengagement-by depression of said push buttonyth'edast specified means affordingalso sliding disengagement of said bridging contact from said'stationary contacts for following movement-oi said bridging contact perpendicularly of the plane of said stationary contacts-as a function'of thebias' of saidpush button, and said trip unit comprising means acting through said interconnectionswith said switch unit to efiect the aforementioned sliding disengagement of-said bridging contact from said stationary contacts; said trip'unit requiring for resetting thereof depression of said push button as in the-case ofuse' of said push button to disengage said bridgingcontact from said-stationary contacts andsaid trip unitretaining saj i bridging contact out of alignment with said stationary contacts pending movement of said push button to a position necessitating its release for reengagement of the realignedcontacts.

16. A composite device comprising separate units, one having a switch mechanism inclusive of tripping means affording it only =manual tripping and another of one'of said units having automatic tripping mechanism 'forsaid switch mechanism, said tripping meansrequiring manual resetting after tripping operation thereof and interconnections' between said switch mechanism and said tripping mechanism rendering the former responsive directlyto the latter and rendering the formerefiective-toreset the-latter, said units having protecting parts enabling assembly .of. said units in an intimateside by side'relation in. which said protecting parts afford protecting enclosure of said mechanisms and said interconnections. l I

17. A composite devicecomprising separate units, one having a switchmechanism and others eachhaving an automatic 'tripping'mechanism for said switch mechanism, and means interconnecting said mechanismswhen said units are l8.'A composite'device comprising separate units, one having a switch biased inone direction and provided with arectilinearly 'moy blfi' push button to trip it against its bias, and other of said units each having -'automatic trippin'g'means for said switch, and means interconnecting said units when mascara a side] 'byfsid' e relation to" subject said switch to tripping 'directlyjby said tripping units'individually, allsaid units each having enclosing parts providing.protecting enclosure or said switch, saidtripping'means and said interconnectingmeans. Z v

19. In combination, a switch, a thermally responsive device, interconnections between said contacts, a bridging contact, andsupportingjand operating means [ior said bridging contact coinprising an element normally biased to yieldingly hold said bridging "contactin alinementwith said stationary contacts, a push button, and biasing means holding said bridging contactin engagement With'saidstationar'y contacts subject to disengagement by saidpush button through movement of said bridging contact perpendicularly of the plane of saidstationary contacts, said element being movable againstits bias to move said bridging contact out o1 alinement with said stationary contacts thereby" to "disengage said bridging contact'irom said stationary contacts and to free said bridging contact 'tor'movemcnt past said stationary contactsby said biasing means, said contactsthen remaining disengaged pending a given-subsequent "operation of said push button.

' 21. In a switch, in combination, stationary contacts, a bridging contact, a supporting member for said bridging contact, a reciprocable member for moving said" supporting member in in alinement with said stationary contacts, a

, push button secured to said reciprocable member and means biasing'said push button for movementin one direction 'to aiiord" engagement of said bridging contact withfsaid stationary con-- 'tacts when in alineinent subje'cttodiseng'agemerit by depression of saidpush button, said supporting member being movable against its bias to move said bridging contact-out of-alinerne'nt with said stationary contactsthereby 'todisngage said bridging contact from'said stationary contacts and to 'freesaid bridging contact for movement past said stationary contacts as a function of the bias of said" push button, said contacts then remaining "disengaged pending a given subsequent operation of saidpush button.

22. I'n' a protective switch device, in combination, a switch, an electrically controlled trip and interconnections therebetween, said switch comrising stationary contacts, abridging contact and supporting and operating'means for said bridging contact including an element normally biased to yieldingly hold said bridgin contact in' aiinement with said stationary contacts; a push button and biasing means normallyholding said bridging contact in engagement with said stationary contacts subject to disengagement by said push button through movement of said-bridging contact perpendicularly of the plane of said stationary contacts, said element being movableagainst its bias to move said bridging contact out of alinement with saidstationary contacts and to free said bridging contact for movement past said stationary contacts as a function of said biasing means and said trip comprising means acting through said interconnections with said switch to effect the aforementioned movement of said element against its bias.

23. In a protective switch device, in combination, a switch, and electrically controlled trip and interconnections therebetween, said switch comprising stationary contacts, a bridging contact,

a supporting member for'said bridging contact, a reciprocable member for moving said supporting member in reverse directions, means biasing said supporting member to yieldingly hold said bridging contact in alinement with said stationary contacts, a push-button secured to said reciprocable member and biased for movement in one direction to afford engagement of said bridging contact with said stationary contacts when in alinement subject to disengagement by depression of said push button, said supportin member being movable against its individual bias to move said bridging contact out of alinement with said stationary contacts thereby to disengage said bridging contact from said stationary contacts and to free said bridging contact for movement 14 past said stationary contacts as a function of the bias of said push button, and said trip compris= ing means acting through said interconnections with said switch to eiTect th aforementioned movement of said supporting member against its individual bias.

CLARENCE W. KUHN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

